Quarterly report [Sections 13 or 15(d)]

Marketable Securities - Narrative (Details)

v3.25.2
Marketable Securities - Narrative (Details)
3 Months Ended 6 Months Ended
Jul. 31, 2025
USD ($)
security
Jul. 31, 2024
USD ($)
Jul. 31, 2025
USD ($)
security
Jul. 31, 2024
USD ($)
Jan. 31, 2025
USD ($)
security
Investments, Debt and Equity Securities [Abstract]          
Investment income, interest $ 5,800,000 $ 7,000,000.0 $ 10,900,000 $ 15,300,000  
Debt securities in an unrealized loss position | security 93   93   40
Unleased loss position $ 311,600,000   $ 311,600,000   $ 140,000,000
Expected credit losses $ 0   $ 0   $ 0